I just want to say that I'm having the exact same issue.  Quickbooks 2019 and 2020 work on my old laptop but I purchased a new one recently and installed Quickbooks and neither 2019 or 2020 will open.  I've tried the Tool Doctor, reinstalling, turning off my firewall....nothing has worked.  Looks like I'm back on my old laptop with hours wasted trying to figure this out.